The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Internal combustion engines may utilize electronic fuel injection (EFI) to meter fuel to the engine. Common types of EFI systems include manifold injection, port injection, pre-combustion chamber injection, and direct injection. One or more fuel injectors may be utilized to deliver fuel to the engine. Fuel injectors generally include a nozzle located at a tip thereof and a valve. The fuel injectors may be selectively energized to open the valve and atomize the fuel by pumping the fuel through the tip under pressure. For example, power may be supplied to a solenoid to open the valve.
The process of determining and delivering the fuel to the engine at the appropriate time is known as fuel metering. Fuel metering is important to controlling an engine's air-fuel ratio to achieve the desired engine starting and operating performance, emissions, driveability, and fuel economy.
A period of time that the fuel injectors are energized is referred to as a pulse width. Typically, the pulse width for each of the fuel injectors is determined based on a desired quantity (e.g., mass) of fuel, the size of the fuel injectors (i.e. fuel flow capacity), and the pressure of the fuel that will be supplied. To simplify the determination of the pulse width, some systems assume that the fuel injectors provide linear fuel flow over the range of fuel pressures supplied to the fuel injectors. As a practical matter, fuel injectors are typically capable of linear fuel flow over a limited range of fuel pressures.
The number and size of the fuel injectors and the fuel pressure largely depend on the size of the engine and its maximum power output. However, the maximum fuel pressure that can be used is limited by the amount of power available to operate the fuel injectors. The number and size of the fuel injectors is also dependent on the linear flow range of the fuel injectors.
Engines with large displacement and/or high power output may require two or more fuel injectors per cylinder. Implementing such a fuel injection system may require additional engine controllers to drive the additional fuel injectors. The additional controllers may require additional packaging space and wiring. Complicated control methods for turning on and off the additional fuel injectors to obtain the increased fuel flow may also be required. The complexity of such a fuel injection system increases the cost of developing and producing such a system.